1) Clinico-pathologic Considerations

It is difficult to obtain tissue diagnosis of this malignancy, and clinical presentation is often the only means of diagnosis. Attempts at fine needle aspiration and cytology obtained by means of brushings at ERCP may be successful in confirming malignancy, but frequently these tests are falsely negative, particularly in small, potentially resectable tumours.

The CA 19-9 serum antigen is often promoted as a diagnostic marker for pancreatico-biliary malignancy; in the setting of obstructive jaundice this is an unreliable marker, and overall only about half of patients with elevated CA 19-9 and obstructive jaundice are ultimately shown to harbour malignancy.

Intrahepatic cholangiocarcinoma is frequently mistaken for hepatocellular carcinoma or metastatic disease from an unknown primary site.

For those patients who undergo curative-intent resection, poor prognostic factors include positive margins, nodal involvement, poorly-differentiated tumours and vascular invasion. For intrahepatic cholangiocarcinomas large primary size (>5cm) and intrahepatic satellite lesions also denote a worse prognosis.

2) Diagnostic Pathology

Over 90% of bile duct cancers are adenocarcinomas. Generally they are divided into 3 groups based on prognosis and potential management: intrahepatic, perihilar and extrahepatic (or distal) cholangiocarcinomas. The relative distributions are 10% for intrahepatic disease, 50% for perihilar, 20% for distal, and 10% multifocal/diffuse. Perihilar tumours are defined as arising between the cystic duct – common duct junction and the confluence of the hepatic ducts (these are also known as Klatskin tumours).

These tumours tend to grow slowly, with local invasion. They are often well differentiated and frequently are mucin producing. Histologically, they may be sclerosing, papillary, or nodular. The papillary variety may be multifocal, is more common distally and may have a better prognosis.